Headrests referred to as active headrests are known, such active headrests comprising two parts, a fixed part and a moving part, the moving part being movable from a rest position, in which the moving part is attached to the fixed part, to an active position in the event that the vehicle receives a rear impact. In the active position, the moving part is separated from the fixed part and moved towards the head of the occupant in the seat, thereby reducing the distance that the head travels until reaching its support in the headrest, and therefore reducing the risk of the occupant suffering whiplash.
Spanish Patent Application No. ES2344496A1 describes a headrest for motor vehicle seats comprising a fixed part, a moving part movable with respect to the fixed part from a rest position to an active position, connection means connecting the fixed part and the moving part to determine the path and the position of the moving part, and a drive system comprising a drive device for driving and moving the moving part with respect to the fixed part.